Championship side Derby County won 5-3 on penalties to knock Premier League Southampton out of the FA Cup.
Redmond was the only player to miss in the shootout, firing high and wide to give Derby the advantage at St Mary’s after a thrilling 2-2 draw.
It was Rams skipper Richard Keogh who scored the winning penalty to send Lampard’s side through to a fourth round clash with Accrington Stanley.
Derby thought they had taken the lead in the 38th minute as Craig Bryson slotted in after Martyn Waghorn’s lay-off.
Southampton scored two goals in as many minutes to seize control of the tie.
The hosts took the lead in the 67th minute through Stuart Armstrong’s header, the Scotland international nodding in from close range after Shane Long’s header was blocked on the line by Scott Malone.
And Nathan Redmond was played through just a minute later and calmly lifted the ball over keeper Kelle Roos to score Southampton’s second.
But the goal was checked by the VAR and Waghorn was adjudged to have been just offside as the ball was played into him and the goal was ruled out.
But Derby snatched a goal back just six minutes later. Harry Wilson whipped a free-kick in and, despite Waghorn’s attempt to get a head on the ball, it appeared to evade everyone and nestled in the far corner.
The goal was once again checked by the VAR, but was allowed to stand.
And the comeback was complete with fewer than ten minutes remaining when Wilson turned provider as his cross found Waghorn unmarked in the box to head home.
Both teams had chances to win it late on – Tom Lawrence heading over from close range for Derby and Elyounoussi going close for Southampton.
Redmond wasted a golden opportunity to restore Saints’ lead in the 111th minute, firing straight at Roos after being slipped in by Oriol Romeu, before his off-target spot-kick in the shoot-out proved decisive.